16-8735795-G-A

Position:

chr16-8735795-G-A

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2BP4_StrongBS1_Supporting

The NM_020686.6(ABAT):c.56G>A(p.Arg19His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000399 in 1,603,838 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000053 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000039 ( 0 hom. )

Consequence

ABAT
NM_020686.6 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: -1.00

Variant links:

Genes affected

ABAT (HGNC:23): (4-aminobutyrate aminotransferase) 4-aminobutyrate aminotransferase (ABAT) is responsible for catabolism of gamma-aminobutyric acid (GABA), an important, mostly inhibitory neurotransmitter in the central nervous system, into succinic semialdehyde. The active enzyme is a homodimer of 50-kD subunits complexed to pyridoxal-5-phosphate. The protein sequence is over 95% similar to the pig protein. GABA is estimated to be present in nearly one-third of human synapses. ABAT in liver and brain is controlled by 2 codominant alleles with a frequency in a Caucasian population of 0.56 and 0.44. The ABAT deficiency phenotype includes psychomotor retardation, hypotonia, hyperreflexia, lethargy, refractory seizures, and EEG abnormalities. Multiple alternatively spliced transcript variants encoding the same protein isoform have been found for this gene. [provided by RefSeq, Jul 2008]

ABAT links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.06165144).

BS1

Variant frequency is greater than expected in population sas. gnomad4 allele frequency = 0.0000526 (8/152128) while in subpopulation SAS AF= 0.000415 (2/4824). AF 95% confidence interval is 0.000073. There are 0 homozygotes in gnomad4. There are 3 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
ABAT	NM_020686.6 linkuse as main transcript	c.56G>A	p.Arg19His	missense_variant	2/16	ENST00000268251.13	NP_065737.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ABAT	ENST00000268251.13 linkuse as main transcript	c.56G>A	p.Arg19His	missense_variant	2/16	1	NM_020686.6	ENSP00000268251	P1

Frequencies

GnomAD3 genomes

AF:

0.0000526

AC:

AN:

152128

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

Gnomad SAS

AF:

0.000415

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000605

AC:

AN:

231476

Hom.:

AF XY:

0.0000639

AC XY:

AN XY:

125118

show subpopulations

Gnomad AFR exome

AF:

0.0000689

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000566

Gnomad SAS exome

AF:

0.000284

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000384

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000386

AC:

AN:

1451710

Hom.:

Cov.:

AF XY:

0.0000499

AC XY:

AN XY:

721154

show subpopulations

Gnomad4 AFR exome

AF:

0.0000598

Gnomad4 AMR exome

AF:

0.0000230

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000253

Gnomad4 SAS exome

AF:

0.000344

Gnomad4 FIN exome

AF:

0.0000385

Gnomad4 NFE exome

AF:

0.0000154

Gnomad4 OTH exome

AF:

0.0000499

GnomAD4 genome

AF:

0.0000526

AC:

AN:

152128

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74314

show subpopulations

Gnomad4 AFR

AF:

0.0000483

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000193

Gnomad4 SAS

AF:

0.000415

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000441

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000286

Hom.:

Bravo

AF:

0.0000227

ExAC

AF:

0.0000660

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Gamma-aminobutyric acid transaminase deficiency

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 24, 2022

This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 19 of the ABAT protein (p.Arg19His). This variant is present in population databases (rs780368959, gnomAD 0.02%). This variant has not been reported in the literature in individuals affected with ABAT-related conditions. ClinVar contains an entry for this variant (Variation ID: 529790). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The histidine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.079

BayesDel_addAF

Benign

-0.29

BayesDel_noAF

Benign

-0.36

CADD

Benign

5.4

DANN

Benign

0.93

DEOGEN2

Benign

0.048

T;T;.;T;T;.;.;T;T

Eigen

Benign

-1.1

Eigen_PC

Benign

-1.2

FATHMM_MKL

Benign

0.042

LIST_S2

Benign

0.72

.;T;T;T;T;T;T;.;T

M_CAP

Benign

0.020

MetaRNN

Benign

0.062

T;T;T;T;T;T;T;T;T

MetaSVM

Benign

-0.89

MutationAssessor

Benign

1.3

L;.;.;.;L;.;.;L;.

MutationTaster

Benign

0.79

N;N;N;N;N

PrimateAI

Benign

0.23

PROVEAN

Benign

-1.2

N;N;N;N;N;N;N;N;N

REVEL

Benign

0.20

Sift

Benign

0.32

T;T;T;T;T;T;T;T;T

Sift4G

Benign

0.20

T;T;D;T;T;T;T;T;T

Polyphen

0.0010

B;.;.;.;B;.;.;B;.

Vest4

0.13

MutPred

0.43

Loss of MoRF binding (P = 0.0071);.;Loss of MoRF binding (P = 0.0071);Loss of MoRF binding (P = 0.0071);Loss of MoRF binding (P = 0.0071);Loss of MoRF binding (P = 0.0071);.;Loss of MoRF binding (P = 0.0071);Loss of MoRF binding (P = 0.0071);

MVP

0.56

MPC

0.38

ClinPred

0.015

GERP RS

-1.8

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.0

Varity_R

0.024

gMVP

0.35

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over